1. Field of the Invention
The present invention relates to an apparatus for projecting an image selected among images recorded on a recording medium with the image being arranged in at least two lines.
2. Description of the Prior Art
In a projector such as a film reader or film reader-printer there are used two different types of films as shown in FIGS. 1 and 2. The film 2 shown in FIG. 1 is the first type of film on which images 1 are recorded arranged in single line. The film 4 shown in FIG. 2 is the second type one on which images 3 are recorded arranged in two lines. Designated by m are marks used for retrieving the desired one of the recorded images. The retrieving marks m have a different density from the image portion of the film and have been provided along one long side (FIG. 1) or along two long sides of the film (FIG. 2).
The method for taking pictures employing the second type of film 4 is generally called duo-method. According to the duo-picture taking method, the film 4 loaded on a camera is at first moved in the forward direction from the leading end to the trailing end of the film while taking pictures serially one half area of the film along one long side thereof (first line). After the end of picture taking in the first line, the film is taken out from the camera and then reloaded in the camera reversing the leading end and the trailing end of the film. Now, pictures are serially taken on the remaining half area along the other long side of the film from the trailing end to the leading end (second line). Therefore, after the end of all of exposures, the film has recorded images arranged in two lines, a first and a second line. As viewed in FIG. 2, the leading end of the film is on the left-hand side and the trailing end is on the right-hand side. For the sake of explanation, the images recorded in two lines on the film 4 are numbered in the order of the exposed frame (in practice such numbers are never recorded in the film). Retrieving marks m are really provided along both sides of the film one mark to one image frame.
In the film for the duo-method described above, as seen in FIG. 2, the images in the second line are upside down as compared with the images in the first line. One image frame with one retrieving mark in the first line and the corresponding one frame with one retrieving mark in the second line are symmetrical relative to the center on the center line of the film passing through between the first line images and the second line images.
When such a duo-film as the film 4 is used, there arises a problem in projecting any desired image selected from the images recorded on the film. For such a duo-film it is the conventional method to project two images in the first and second lines at the same time on a projection surface such as a screen. Since two images are projected on the screen at the same time, the observer can not understand at once which is the desired image. Furthermore, it is required for the operator or observer to turn the projected image to its proper position for observation. This work causes the operator problems. The problem is enhanced when there is used a film having images recorded therein in three or more lines.